This invention pertains generally to cardiovascular procedures such as angioplsaty, angiography and valvuloplasaty, and more particularly to an extendable guidewire and the methods of manufacturing and using the same.
Guide wires are currently used to facilitate the placement of dilatation catheters in the arterial system of a patent for cardiovascular procedures such as angioplasty, angiography and valvuloplasty. The guidewire is typically on the order of 20-50 cm longer thana the catheter to permit the guidewire and the catheter to be advanced relative to each other as they are steered into position within the patient's body. Suitable guidewires are described in U.S. Pat. No. 4,538,622 (Samson et al.) and U.S. Pat. No. 4,569,347 (Frisbie) which are hereby incorporated herein in their entirety.
In the usual procedure to change dilatation catheters, the guidewire is removed from the patient, and an exchange wire is inserted in its place. The exchange wire is substantially longer than the guidewire, and it generally extends outside the patient's body for a distance greater than the length of the catheter. With a dilation catheter having a length on the order of 120-140 cm, for example, a guidewire might have a length on the order of 175 cm, and an exchange wire might have a length on the order of 300 cm. The use of an exchange wire has the obvious disadvantage that it adds extra steps to the angioplasty procedures. In addition, it requires the doctor to have an additional wire for this purpose.
Heretofore, there have been some attempts to eliminate the need for a separate exchange wire by attaching an extension wire to a coronary wire to extend the length of the wire. The two wires are joined together by a crimped connector which requires a special tool. Once the connector has been crimped, the connection is permanent, and the extension wire cannot be removed except by cutting it loose from the coronary wire.
What has been needed and heretofore unavailable is an extension which can be readily connected and disconnected to the guide wire and when in position withiin the patient. The present invention satisfies this need.